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. 2009 Mar 6;10(4):367–373. doi: 10.1038/embor.2009.8

Figure 2.

Figure 2

The effect of tributyltin on coactivator recruitment and activation of RXR-α and PPAR-γ. Titration of fluorescein-labelled PGC-1α peptide by (A) RXR-α and (B) PPAR-γ, in the absence of ligand or in the presence of CD3254 (RXR agonist), UVI3003 (RXR antagonist), BRL49653 (PPAR-γ agonist), CD5477 (PPAR-γ antagonist) or TBT. (C) Stably transfected HGELN PPAR-γ cells were incubated with BRL49653, CD3254 or TBT to measure their effect on the transcriptional activity of the heterodimer formed by Gal4-PPAR-γ and endogenous RXR. (D) To measure the specific effect of the organotin on PPAR-γ and RXR, BRL49653, CD3254 or TBT were also tested in the presence of saturating concentrations of RXR (CD3254)- or PPAR-γ (BRL49653)-specific ligands. Here, 100% activity corresponds to the activity obtained with 1 μM BRL49653. (E) HeLa cells transiently transfected with the reporter recombinant (RXRE)6-TK-Luc and pSG5-RXR-α (human wild-type or mouse RXR-αC437A) were incubated with BRL49653, CD3254 or TBT to assess their agonist potential on an RXR-α homodimer. The antagonist UVI3003 (10 μM) was also used to check the reversibility of TBT (10 nM) binding. (F) The same experiment as in (E) but using (PPRE)3-TK-Luc and pSG5-hPPAR-γ. The antagonist CD5477 was used as a control. HGELN, HeLa ERE (estrogen responsive element) luciferase neomycin; PGC-1α, PPAR-γ coactivator 1α; PPAR-γ, peroxisome proliferator-activated receptor-γ; RXR-α, retinoid X receptor-α; TBT, tributyltin.